question_answer

As per this diagram a point charge \[+q\] is placed at the origin \[O\]. Work done in taking another point charge \[-Q\] from the point \[A\] [co-ordinates \[(0,\,a)\]] to another point B [co-ordinates (a, 0)] along the straight path \[AB\] is [CBSE PMT 2005]

A)            Zero

B)            \[\left( \frac{-qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\sqrt{2}a\]

C)            \[\left( \frac{qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\frac{a}{\sqrt{2}}\]

D)            \[\left( \frac{qQ}{4\pi {{\varepsilon }_{0}}}\frac{1}{{{a}^{2}}} \right)\,\sqrt{2}a\]